This application relates to networks composed of local area networks (LANs) connected by LAN bridges.
A LAN is a network of computing systems (generally referred to as end systems) which are connected by a common communications medium, or bus. Messages are transferred from one end system to another via the LAN by conveying the message, along with the address of the intended recipient end system, onto the common communications bus. Each end system then receives the message and reads the address. If the message address matches the recipient end system's address, the message is processed; otherwise, the message is discarded. Thus, in a LAN, every message is received by every end system; this allows for simple interconnection and rapid communication, but limits the number of end systems that can be effectively interconnected.
When the number of end systems on a LAN becomes unmanageable, or when geographical restrictions prohibit serviceable connection of all end systems on a single LAN, system managers typically organize groups of end systems into several LANs, and use bridges to provide connections between the LANs, forming a LAN/bridge network.